Nothing evokes the good ol’ Republican days like the mighty Reagan era.

Throughout this primary season, GOP presidential hopefuls have often tripped over themselves to name-drop the 40th president of the United States, indicating that a vote for them will mean a return to the conservative glory of the “Great Communicator.”

And, in less bombastic fashion, their wives — and their wives’ choices of clothing — are conjuring the powerful image of Nancy Reagan.

“She had a signature look, because of her background in Hollywood. And she knew what looked good on her,” argues Patsy Cisneros, CEO of Corporate Icon, a California-based image-consultancy firm advising high-level politicians.

While Republican successors Barbara and Laura Bush opted for a preppy aesthetic — think matching twin sets — that could be purchased at the mall, Reagan radiated strength through fashion.

“Wearing powerful colors and suits really did indicate the type of woman she was at the White House,” says Cisneros. “She was the person who looked adoringly at her husband, but she never looked shy or retiring. She looked like power. She had impeccable taste and wanted the White House to have the same feeling it had with Jackie Kennedy.

“She set the tone for first ladies to have significant input into the White House,” she adds.

And the current crop of GOP spouses — Melania Trump, Heidi Cruz, Jeanette Dousdebes Rubio and Karen Waldbillig Kasich — are all taking a page out of Nancy’s style playbook with their own modern updates.

“Any indication of what they will be like in the White House, they are going to tell us through what they choose to wear,” says Cisneros.

Hillary Clinton, for instance, often seemed indifferent to the pressures of image, while Michelle Obama set a completely different style agenda — championing American designers such as Jason Wu and Tracy Reese, wearing budget brands such as Target’s, and often experimenting with edgy silhouettes and hairstyles.

The radiant and dynamic Reagan, on the other hand, used fashion to her advantage by relying on one very simple color.

Dress coats: Melania Trump is red-dy for the White House in a crimson double-breasted coat that’s strikingly similar to one worn by Nancy Reagan (left, with President Reagan) at the White House in 1987.Aaron Bernstein/Reuters; Dirck Halstead/Getty Images

“The idea of wearing bright red has persisted for far longer than I would have predicted. It became a patriotic look and closely associated with politics for such an extended period of time,” she adds.

All of the candidates’ wives have hit the campaign trail in the striking hue — often paired with eye-catching but classic pearls.

“There are little touches here and there going back to the red with a string of pearls that we see echoing across later generations,” says Logothetis of the newest crop of wannabes.

Classic pearls: Karen Kasich (right) celebrates her husband’s strong showing in theNew Hampshire primary in a burgundy sheath accented with a multistrand pearl necklace, an accessory favored by Reagan. But the former first lady, here in 1987, rarely bared her arms and preferred a more conservative silhouette.Gianni Ferrari/Getty Images; AP Photo/Jim Cole

Beyond her trademark color, Reagan was known for her stylish, conservative stable of beautifully cut suits and jackets — from nubby Chanel to trench-inspired toppers.

“Nancy wore colorful business looks. And rarely did she not have a jacket over her nonformal wear. That was a beautiful look on her,” says Cisneros.

Similarly, Cruz — an executive at Goldman Sachs — favors bold pastel suits, while Trump is now seen at campaign events with a red or pink overcoat draped over her shoulders.

According to Valerie Steele, director of the Museum at FIT, former actress Reagan brought Hollywood glamour to 1600 Pennsylvania Ave. But there was restraint. While her choices were high-fashion, they weren’t too noisy or trend-focused.

“It wasn’t ‘Dynasty.’ I think she straddled the line,” says Steele.

“She did do the one-shouldered thing, and that was daring. She liked the [designer James] Galanos look [which she wore to the 1981 Inaugural Ball]. It was a beautiful dress and she was slim, so she could wear that.”

But otherwise, she opted for a more covered-up approach.

The same can now be said for Melania Trump, a model who used to appear at events with her heaving bosom on full display.

Since her husband became a viable candidate, her looks have softened. And her necklines are much less revealing.

Power suits: Heidi Cruz (right), an executive at Goldman Sachs, wears a pink two-piece that exudes feminine power — and shares a similar hue and cut to an outfit worn by Nancy Reagan when she was the first lady of California.Jay Paul/Bloomberg; Conde Nast Archive/Corbis

Reagan’s look was deliberate, all the way down to her perfectly layered and teased ’do, which she never changed.

“She never had an off day,” says Cisneros. “You wouldn’t catch her saying, ‘Today I will wear a head band or ponytail.’ She didn’t do that. She knew her signature look, and that included grooming. She knew it was also going to work on-camera.”

Likewise, the latest offering of GOP wives are always photographed with their hair blown out perfectly straight — sometimes with a flip or added volume at the top.

Still, there is one major area of departure: These fitness-obsessed gals tend to show more skin — particularly their arms.

Rubio is a former cheerleader for the Miami Dolphins, while Kasich is a marathon runner with guns like Michelle Obama’s — and she’s not afraid to show them off in classic shift dresses.

Reagan, meanwhile, rarely showed off her biceps.

As Steele puts it: “She came from a generation when we didn’t have to have Madonna-muscular arms.”

“Heidi Cruz has a few things in common with Nancy Reagan,” says Christina Logothetis, a Washington, DC-based image consultant. “First [there] is the overall femininity of her look, both in the colors she chooses — reds and pinks at key appearances — and with styles that sometimes include ruffles or rosettes. The other thing is the projection of wealth.”

“Melania Trump was a model and has a natural bent toward the glamorous — no matter what she wears,” says Logothetis. But, “she is definitely trying to channel Nancy Reagan as much as she can get away with.”

Karen Kasich

AP Photo/Carlos OsorioAge: 52Career: Public relations; former vice president of a healthcare ad agencyMarried for: 19 yearsChildren: 2Fun fact: She is an avid runner.Her look: Classic but without the polish of the other women: sporty, neutral shifts that show off her toned arms

“Karen Kasich looks much more like a governor’s wife or perhaps a House member than she does a first lady at this point,” says Logothetis. “Her style is simply professional, but not very distinctive, like she probably put the whole thing together herself in one afternoon at the mall. She looks totally appropriate, but it’s almost a nonstyle style.”